Four-layer crimping structure of small three-piece irregular can and seaming method thereof

ABSTRACT

A crimping structure of a small irregular can and a manufacturing method thereof, in particular to a seam method for buckling a bottom by stamping. The crimping structure includes a can body crimping edge and a can bottom crimping edge made of a plate material of a same type, wherein the can body crimping edge covers the can body crimping edge to crimp 90 degrees inward. A four-layer structure with a first can body crimping edge layer, a can bottom crimping edge layer, a second can body crimping edge layer and a can bottom layer, arranged in a sequence, is formed. By adopting the above-mentioned four-layer crimping structure of the small three-piece irregular can, the sealing performance of the can body is greatly enhanced, effectively improving the moisture-proof performance, thereby protecting the safety of food in the can.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the national phase entry of International Application PCT/CN2014/090667, filed on Nov. 10, 2014, which is based upon and claims priority to Chinese Patent Application No. 201310736948.9, filed on Dec. 26, 2013, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a crimping structure of a small irregular can and a manufacturing method thereof, in particular to a seaming method for buckling a bottom by stamping.

BACKGROUND

The existing seaming method in the prior art for bottom cover of a canister mainly includes molding by a seam assembly machine, the principle thereof is as follows. A bottom and a top of the canister are firstly placed on a canister body, then the bottom and top are clamped with the canister body by two disks, so that the canister body, the bottom and top of the canister rotate together, then a crimping roller is leaned up. The bottom and top of the canister and the edge of the canister body are crimped along the groove-shaped curve of the roller. When the roller completely leans against the canister body, the crimping is basically formed. Finally, a secondary correction roller leans up to tightly compress the crimping and eliminate rebound, so that the crimping is in a required shape. This method is mainly used for forming the seam in round canisters. However, in the process of seaming an irregular can, because the four sides are not circular, the distances between each point of the seam part and the center of the can body are not equal, and the crimping roller cannot move in a circumferential direction, the seaming method in which the roller of the round can moves in the circumferential direction and the can body rotates, is not suitable for crimping the irregular can. For example, for the seam of small irregular boxes such as chewing gum boxes, the irregular can seaming machine used must be in a structural form in which the can body is stationary and the seaming roller performs profiling movement. There are two basic forms of profiling seam for the irregular can, one is a can-type explorator and the other is a non-can-type explorator. The two methods make the design and requirements of the crimping roller more complex and the manufacturing more difficult. Because the turn curvature changes greatly, the inertia change of the crimping roller in the area also increases dramatically, which seriously affects the quality of the seam, limits the improvement of the production capacity, and is prone to the deficiencies such as the seam is not tight, the accuracy is not enough, the wrinkle is produced and the crimping is damaged and broken by rolling, etc., which do not meet the quality standards. Therefore, most of ordinary small irregular cans are formed by adopting the process of die stamping and seaming.

In the prior art, the method of die stamping and seaming of the irregular can body and the bottom (top) of the irregular can adopts double crimping. The process is simple and the defects of this method are that it has poor sealing performance and may cause leakage, so this method cannot be used for the canisters requiring higher sealing performance.

SUMMARY

The objective of the present invention is to provide a four-layer crimping structure of a small three-piece irregular can and a seaming method thereof. In the method, a die stamping and crimping is used to change the crimping structure in the prior art, effectively improving the sealing performance of the crimping. Moreover, the production method is simple and the production efficiency is high.

The four-layer crimping structure of the small three-piece irregular can of the present invention includes can body crimping edge 11 and can bottom crimping edge 21 made of a plate material of the same type. Can body crimping edge 11 covers the can bottom crimping edge 21 to crimp 90 degrees inward. A four-layer structure with a first can body crimping edge layer, a can bottom crimping edge layer, a second can body crimping edge layer and a can bottom layer, arranged in a sequence, is formed.

According to the four-layer crimping structure of a small three-piece irregular can, the can body and the can bottom, made of the plate material with a thickness of 0.23 mm, have a can body crimping edge with a length of 4.5 mm and a can bottom crimping edge with a length of 3 mm.

The above-mentioned seaming method of the five-layer crimping structure of the small three-piece irregular can includes the following steps: {circle around (1)} selecting a plate material with the thickness of 0.23 mm for blanking and cutting to make a can body and a can bottom respectively; {circle around (2)} pre-bending an end of can body crimping edge 11, a pre-bending length of the end is 0.8-1.2 mm; {circle around (3)} placing the can bottom inside the can body and sleeving the can bottom on a bottom die with the root of can bottom crimping edge 21 and the root of can body crimping edge 11 on a same horizontal line; {circle around (4)} forming a first stamping on the can bottom and the can body, a first stamping upper die is a crimping die, the die cavity of the crimping die is the union of a semi-circular arc and a rectangle, the diameter of the semi-circular arc is 2.1 mm, and the size of the rectangle is 2.1×1.05 mm; {circle around (5)} forming a secondary stamping based on step {circle around (4)} a secondary stamping upper die is a linear die.

By adopting the four-layer crimping structure of the small three-piece irregular can, compared with the prior art, the sealing performance is greatly enhanced, effectively improving the moisture-proof performance, thereby protecting the safety of food in the box. By adopting the die pressing and seaming method of the present invention, an “iron tongue” will not be generated in the crimping and no void is formed inside the interior of crimping. The production method is simple and the production efficiency is high.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic structural diagram of the small three-piece irregular can of the present invention.

FIG. 2 is an enlarged view of the four-layer crimping structure shown in FIG. 1.

FIG. 3 is a structural diagram of a crimping edge before the four-layer crimping structure of the small three-piece irregular can of the present invention is formed by seaming method.

FIG. 4 is an enlarged view of FIG. 3.

FIG. 5 is a schematic diagram of the crimping die.

FIG. 6 is a schematic diagram of the linear die.

FIG. 7 is one of the schematic diagrams of the crimping structure after the crimping is formed.

FIG. 8 is another one of the schematic diagrams of the crimping structure after the crimping is formed.

DETAILED DESCRIPTION

Hereinafter, the present invention is described in detail with reference to the drawings,

As shown in FIGS. 1, 2, and 3, the four-layer crimping structure of the small three-piece irregular can of the present invention includes can body 1, can body crimping edge 11, can bottom 2 and can bottom crimping edge 21 made of the plate material of the same type. When can body 1 and can bottom 2 are made of the plate material with the thickness of 0.023 mm, the length of can body crimping edge 11 of the can is 4.5 mm, the length of can bottom crimping edge of the can is 3 mm. Can body crimping edge 11 covers the can bottom crimping edge 21 to crimp 90 degrees inward. A four-layer structure with first can body crimping edge layer 111, can bottom crimping edge layer 212, second can body crimping edge layer 113 and can bottom layer 214 arranged in sequence is formed. With such a crimping structure, there is no void inside the crimping, effectively improving the sealing performance of the seam structure. Can body crimping edge 11 and can bottom crimping edge 21 are crimped inward, so that there is no visible flange at the bottom of the can body, the overall aesthetic effect of the can body is not affected by the crimping of the bottom cover, and the appearance is also beautiful.

The above-mentioned seam method of the four-layer crimping structure of small three-piece irregular can is as follows.

First, the can bottom and the can body are manufactured according to the prior art, as shown in FIGS. 3, 4, 5 and 6.

The first step: pre-bending end 11 a of can body crimping edge 11, the pre-bending length of the end 11 a is 0.8-1.2 mm, as shown in FIGS. 3 and 4.

The second step: placing can bottom 2 inside can body 1 and sleeving can bottom 2 on the bottom die with root 21 b of can bottom crimping edge 21 and root 11 b of can body crimping edge 11 on the same horizontal line, as shown in FIG. 4.

The third step: forming the first stamping on the can bottom and the can body, the first stamping upper die is a crimping die, the die cavity of the crimping die is the union of a semi-circular arc and a rectangle, the diameter of the semi-circular arc is 2.1 mm, and the length of long side A of the rectangle is 2.1 mm, the length of short side B of the rectangle is 1.05 mm, as shown in FIG. 5.

The forth step: forming the secondary stamping based on the third step to tightly compress the crimping and eliminate rebound, the secondary stamping upper die is a linear die. As shown in FIG. 6, the crimping structure shown in FIG. 7 is obtained by using the linear die shown in FIG. 6. Certainly, according to the customer's requirements for linear shapes, different linear shapes can be obtained by changing the linear die to meet the customer's needs. As shown in FIG. 8, the linear shape is flat. 

1. A four-layer crimping structure of a small three-piece irregular can, comprising: a can body crimping edge and a can bottom crimping edge made of a plate material of a same type, wherein the can body crimping edge covers the can body crimping edge crimp 90 degrees inward; a four-layer structure with a first can body crimping edge layer, a can bottom crimping edge layer, a second can body crimping edge layer and a can bottom layer arranged in a sequence is formed.
 2. The four-layer crimping structure of the small three-piece irregular can according to claim 1, wherein a can body and a can bottom made of a plate material with a thickness of 0.23 mm have the can body crimping edge with a length of 4.5 mm and the can bottom crimping edge with a length of 3 mm.
 3. A seam method of a five-layer crimping structure of the small three-piece irregular can according to claim 2, comprising the following steps: {circle around (1)} selecting the plate material with the thickness of 0.23 mm for blanking and cutting to make the can body and the can bottom respectively; {circle around (2)} pre-bending an end of the can body crimping edge, wherein a pre-bending length of the end of the can body crimping edge is 0.8-1.2 mm; {circle around (3)} placing the can bottom inside the can body and sleeving the can bottom on a bottom die with a root of the can bottom crimping edge and a root of the can body crimping edge on a same horizontal line; {circle around (4)} forming a first stamping on the can bottom and the can body, wherein a first stamping upper die is a crimping die, a die cavity of the crimping die is an union of a semi-circular arc and a rectangle, a diameter of the semi-circular arc is 2.1 mm, and a size of the rectangle is 2.1×1.05 mm; {circle around (5)} forming a secondary stamping based on step {circle around (4)}, wherein a secondary stamping upper die is a linear die. 